The battle over Scotland's future as part of the United Kingdom has begun. Last week, politicians on both sides of the border set out passionate arguments for and against Scottish independence. All three of Britain's main political parties are committed to preserving the union. In a speech in Edinburgh on Feb. 15, Britain's prime minister, David Cameron, said he would "fight with everything I have to keep our United Kingdom."

A referendum on independence was promised by the Scottish Nationalist Party, which won a landslide in elections to the Scottish parliament last May. After much wrangling, Cameron agreed to a referendum, but on his own terms. Scotland's first minister, SNP leader Alex Salmond, suggested a referendum might put more than one question to voters, not just offering independence, but also greater autonomy for Scotland, including greater tax raising powers. Under this watered-down version of independence, commonly known as "devo max," Scotland would remain part of the U.K., with a single currency and defense force, but Edinburgh would control Scotland's domestic policy and economy. A YouGov poll in January found that Scottish voters were almost 60/40 in favor of devo max, but on full independence, the figures were reversed, with 39 percent for and 61 percent against.

Cameron will only accept a straight yes-no referendum on independence. In a ploy to encourage a "no" vote, however, the prime minister has hinted that he would be willing to consider a version of devo max, but only after a referendum on independence has been lost.